Semiconductor development apparatus and method using same

ABSTRACT

A knife edge ring apparatus is provided for use during semiconductor manufacturing which includes a ring-shaped body having an inner side wall, an outer side wall and a top surface having a predetermined width. A multi-staged inclined portion is formed in the outer side wall and a plurality of discharge holes penetrate the body. Each of the discharge holes have an inlet associated therewith positioned at the inclined portion. The knife edge ring allows developer and cleaning solution to be discharged away from the wafer. A method of cleaning the bottom surface of a semiconductor wafer is also provided which employs the use of the knife edge ring. Developer is supplied onto the top surface of a wafer. Spraying solution is sprayed onto the bottom surface of the wafer. The knife edge ring guides the developer and the cleaning solution remaining on the bottom surface of the wafer&#39;s edge along an inclined portion formed at an outer side wall of the knife edge ring and causes the developer and the cleaning solution to flow into a plurality of discharge holes.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Divisional of U.S. non-provisional application Ser. No.11/605,976, filed Nov. 30, 2006, which is incorporated herein byreference in its entirety.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a semiconductor development apparatusand more particularly to a knife edge ring capable of easily dischargingdeveloper and cleaning solution remaining on a bottom surface of a waferduring semiconductor manufacturing.

This application claims priority from Korean Patent Application No.10-2006-0015335, filed Feb. 16, 2006, the disclosure of which is herebyincorporated herein by reference in its entirety as if set forth fullyherein.

2. Discussion of Related Art

Semiconductor devices are manufactured by repeatedly performing variousprocesses such as diffusion, oxidation, deposition, photolithography andcleaning. In the photolithography process, a photosensitive film made ofa photoresist is coated on the wafer with a predetermined thickness, thewafer is exposed to light using a reticle in which a desired pattern isdesigned, and the exposed photosensitive film is removed through adeveloping process. During this developing process, a wafer to beexposed is rotated at a constant speed while a predetermined amount ofdeveloper is supplied on the wafer. A cleaning solution is then suppliedto the bottom surface of the rotating wafer. The wafer is then withdrawnand mounted on a top surface of a bake plate and baked at apredetermined temperature.

As the developer is supplied to the upper surface of the rotating wafer,the developer moves toward the edge by centrifugal force and some of thedeveloper forms a liquid droplet on the wafer's bottom surface. Inaddition, the cleaning solution directed to the wafer's bottom surfacemay not be entirely discharged. This remaining solution may form anotherliquid droplet toward the edge of the wafer's bottom surface. When thesedroplets combine to form a large size droplet, this droplet may remainon the edge of the wafer's bottom surface. When the wafer undergoes thebaking process, this large liquid droplet migrates toward the side ofthe wafer and is vaporized. This vaporization causes chemical materialto deposit at the periphery of the top surface of the edge of the wafer.This chemical material acts as a contaminant and compromises circuitpatterning at the wafer's edge. This results in product loss due to areduction in the amount of useable wafer.

SUMMARY OF THE INVENTION

The present invention provides a knife edge ring capable of easilydischarging a liquid droplet of a developer and a cleaning solutionremaining on a bottom surface of a wafer's edge during semiconductorwafer processing. The knife edge ring includes a body positioned apredetermined distance from the bottom surface of the wafer. The body isdefined by an inner side wall, an outer side wall and a top surfacehaving a predetermined width. A multi-stage inclined portion is formedin the outer side wall of the body. A plurality of discharge holes, eachhaving an inlet, penetrate the ring body where each of these holes hasan inlet positioned along the inclined portion. The present inventionalso provides for a semiconductor development apparatus and method ofcleaning the bottom surface of a semiconductor wafer utilizing the knifeedge ring.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent to those of ordinary skill in the art bydescribing in detail preferred embodiments thereof with reference to theattached drawings in which:

FIG. 1 is a sectional view illustrating a knife edge ring according toan embodiment of the present invention;

FIG. 2 is a sectional view illustrating the knife edge ring according toan embodiment of the present invention;

FIG. 3 is a sectional view illustrating the knife edge ring according toan embodiment of the present invention;

FIG. 4 is a sectional view illustrating a semiconductor developmentapparatus according to the present invention;

FIG. 5 is a flow chart illustrating an embodiment of a method ofcleaning a bottom surface of a wafer using the semiconductor developmentapparatus according to the present invention; and

FIG. 6 is a flow chart illustrating another embodiment of a method ofcleaning a bottom surface of a wafer using the semiconductor developmentapparatus of the present invention.

DESCRIPTION OF EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention, however, may be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, like numbers refer to like elements throughout.

FIG. 1 is a sectional view illustrating a knife edge ring according toan embodiment of the present invention. Knife edge ring 100 includes aring-shaped body 110 spaced a predetermined distance “h” from a bottomsurface of a wafer W. Body 110 includes an inner side wall 110 a and anouter side wall 110 b and a plurality of discharge holes 111 formedthrough body 110. A multi-stage inclined portion 113 is formed in theouter side wall 110 b and inlets 111 a communicate with discharge holes111 formed in inclined portion 113. Outlets 111 b are formed at a bottomsurface of body 110 and are configured to allow fluid inside holes 111to be discharged. The above-described inner side wall 110 a is an innerwall of a center hole 112 of body 110.

Multi-stage inclined portion 113 is comprised of a first inclinedportion 113 a and a second inclined portion 113 b connected to firstinclined portion 113 a, from an upper portion of outer side wall 110 b.The first inclined portion 113 a is steeper than the second inclinedportion 113 b (β>α). Furthermore, the angle of inclination (α, β) of thefirst and second inclined portions 113 a and 113 b is an obtuse anglewith respect to the bottom surface of body 110 and may be, for example,150° to 170°.

In a top surface 110 c of body 110, the width “t” of a connectionbetween the inner side wall 110 a and the outer side wall 110 b may be,for example, 0.1 to 0.5 mm. The inner side wall 110 a and the topsurface of body 110 may be maintained at right angles with respect toeach other. Alternatively, a corner at which the inner side wall 110 aand the top surface intersect may be tapered to form an inclinedsurface. The discharge hole 111 is formed in body 110 to penetratetherethrough which may be connected to a vacuum suction unit 200 whichincludes a tube 210 coupled to outlets 111 b formed on the bottomsurface of body 110 and a vacuum pump 220 connected to an end of tube210.

A photoresist (not shown) is applied on a top surface of wafer W, but isalso guided to a bottom surface of wafer W at its edge portion causing aliquid droplet to form on the bottom surface. A cleaning solution isdirected to the bottom surface of the edge of wafer under apredetermined spraying pressure. However, the cleaning solution may notbe entirely discharged from the bottom surface of the wafer and anotherliquid droplet may form at the wafer's edge through a space between thebottom surface of the edge of the wafer W and the top surface 110 c ofbody 110. Thus, two liquid droplets composed of the cleaning solutionand a developer combine to form a large-sized liquid droplet “P”.

When the liquid droplet P drops from the bottom surface of wafer W, itdrops toward the inclined portion 113 of body 110. The droplet is guidedby the first inclined portion 113 a and flows into inlet 111 a ofdischarge hole 111 and can be easily discharged outside of body 110through outlet 111 b formed on the bottom surface of body 110. Theinclined portion 113 formed at the outer side wall 110 b of body 110 iscomposed of a multi-stage inclined portion. In particular, inclinedportions 113 a and 113 b define an angles of inclination (α, β). Theseangles are obtuse angles such that liquid droplet P flows fast alongfirst inclined portion 113 a disposed underneath the bottom surface ofthe edge of wafer W and enters inlet 111 a. If the remaining liquiddroplet P does not enter inlet 111 a of first inclined portion 113 a,the droplet is guided to second inclined portion 113 b and flows intoinlet 111 b formed in second inclined portion 113 b. In this manner, theliquid droplet P is easily discharged outside of body 110 throughdischarge holes 111.

A vacuum suction unit 200 is connected to discharge holes 111. As theliquid droplet P flows into discharge hole 111, a suction force frompump 220 is generated inside discharge hole 111 via tube 210 and thedroplet is discharged away from wafer W. Additionally, when the liquiddroplet P remains at the periphery of the inclined portion 113, vacuumsuction unit 200 supplies a suction force to discharge hole 111sufficient to pull the droplet into inlet 111 a. Thus, even if a liquiddroplet P dropped from the bottom surface of the edge of wafer W flowsalong inclined portion 113, but does not enter an inlet, the liquiddroplet P remaining on the inclined surface of inclined portion 113 ispulled into inlet 111 a through the use of vacuum suction unit 200 anddischarged externally. In this manner, it is possible to clean thebottom surface of the edge of wafer W and at the same time clean theouter side wall 111 b of the knife edge ring.

FIG. 2 is a sectional view illustrating the knife edge ring according toan alternative embodiment of the present invention. The knife edge ringincludes a body 110 having an inner side wall 110 a and an outer sidewall 110 b, and a discharge hole 111 formed to penetrate through body110. A multi-stage inclined portion 113 is formed at the outer side wall110 b of body 110. An inlet 111 c of the discharge hole 111 may bepositioned at inclined portion 113. An outlet 111 d of discharge hole111 may be positioned at a bottom surface or a side portion of body 110.A sectional area A of inlet 111 a is larger than a sectional area A′ ofoutlet 111 d where the diameter d of inlet 111 a is larger than thediameter d′ of outlet 111 b. A flow channel inside discharge hole 111may be formed such that it is spaced from inner side wall 110 a from thetop surface 110 c of inclined portion 113 toward the lower side of body110.

FIG. 3 is a sectional view illustrating a knife edge ring according toan alternative embodiment of the present invention in which a protrusion120 is formed at outer side wall 110 b of body 110. Protrusion 120extends from the top surface 110 c of body 110 and includes an inclinedsurface extending from a distal end into body 110 along the lower sideof body 110 and may also be provided at outer side wall 110 b. It ispreferable that the total length of the top surface of the extendingprotrusion 120 and body 110 is, for example, 0.5 mm or less. Theremaining structure of body 110 is similar to that described withreference to FIG. 1 or 2.

In operation, a droplet formed from the developer and a droplet formedfrom the cleaning solution on the bottom surface of the edge of wafer Wcombines to form a droplet P which drops toward inclined portion 113 byits own weight. The dropped liquid droplet P flows toward the lower sideof body 110 along the surface of inclined portion 113. Liquid droplet Pflows into inlet 111 c and into discharge hole 111. The cross sectionalarea A of inlet 111 c is larger than the cross sectional area A′ ofdischarge hole 111 such that liquid droplet P can easily flow into inlet111 c. If liquid droplet P is larger than a predetermined amount, thedroplet can be guided into inlet 111 c. If a vacuum suction is providedto discharge hole 111 from a vacuum suction unit 200 as shown in FIG. 1,liquid droplet P which has flowed into the discharge hole 111 is easilydischarged externally by the suction force generated in discharge hole111. If the liquid droplet P remains at the inclined portion 113 aroundinlet 111 c, the suction force from unit 200 pulls the droplet P intothe discharge hole 111. The vacuum suction force applied to dischargehole 111 is also applied to the bottom surface of the edge of wafer Wthrough inlet 111 c so that it is possible to forcedly pull liquiddroplet P and discharge it externally through discharge hole 111.Additionally, when liquid droplet P flows or is pulled into dischargehole 111, it is guided while contacting the inclined surface ofprotrusion 120 so that the liquid droplet P is easily guided into inlet111 a through inclined portion 113 without splashing on the top surfaceof inclined portion 113.

FIG. 4 is a sectional view illustrating a semiconductor developmentapparatus in accordance with the present invention which includes achuck 190, a developer supply unit 500 and a knife edge ring 100. Chuck190 supports a central bottom surface of wafer W and rotates the waferat a constant speed. Developer supply unit 500 is disposed at the upperside of chuck 190 and supplies a predetermined amount of developertoward the top surface of wafer W. Knife edge ring 100 is positioned tosurround the periphery of chuck 190 and is disposed adjacent to thebottom surface of wafer W a predetermined distance. A cleaning solutionspraying unit 400 is positioned to provide cleaning solution such aspure water toward the bottom surface of wafer W through spraying holes320.

Knife edge ring 100 is comprised of a body 110 having inner and outerside walls 110 a and 110 b and a top surface 110 c having a width of,for example, 0.1 mm to 0.5 mm. A multi-stage inclined portion 113 isprovided in body 110 at outer side wall 110 b thereof. Each of thedischarge holes 111 extends through body 110 and inlet 111 a ispositioned at inclined portions 113 a and 113 b. The cross sectionalarea A of inlet 111 a may be larger than the cross sectional area A′ ofdischarge hole 111. The angle measured between the bottom surface ofbody 110 and inclined portions 113 a and 113 b may be an obtuse anglefrom, for example, 150° to 170°. Discharge hole 111 is connected tovacuum suction unit 200 for forcedly discharging liquid droplet P formedfrom the developer and the cleaning solution introduced thereto throughinlet 111 a. Furthermore, a protrusion 120, which extends from the topsurface 110 c of body 110 and includes an inclined surface inclined froman extending distal end into body 110 along the lower side of body 110,may be further provided at the outer side wall 110 b. It is preferablethat the total length of the top surface of extending protrusion 120 andbody 110 is, for example, 0.5 mm or less. When liquid droplet P formedon the bottom surface of the edge of wafer W flows or is pulled intodischarge hole 111, it is guided while contacting the inclined surfaceof protrusion 120 so that the liquid droplet P can be easily guided intoinlet 111 a through inclined portion 113 without splashing the topsurface of inclined portion 113.

The cleaning solution spraying unit 400 includes an inner cup 310supporting the knife edge ring 100, a plurality of spraying holes 320formed in the inner cup 310, and a cleaning solution supply unit 420which is connected to spraying holes 320 to supply the cleaning solutionthereto. The cleaning solution supply unit 420 is connected to thespraying hole 320 through a tube 410. A plurality of holes 311penetrates inner cup 310 which is connected to discharge holes 111extending through body 110. Holes 311 are connected to tube 210 ofvacuum suction unit 200. A spraying direction of each of the pluralityof spraying holes 320 has a predetermined angle of inclination to directcleaning solution to the bottom surface of the edge of wafer W.

In operation, wafer W is mounted on chuck 190 which rotates at aconstant rotational speed. The developer supply unit 500 supplies apredetermined amount of developer to the top surface of wafer W. Thedeveloper supplied to the top surface of wafer W is applied onto the topsurface of wafer W to remove a photoresist on wafer W and is dischargedthrough the side portion of wafer W. The application of the developer tothe wafer may cause a liquid droplet having a predetermined size to formon the bottom surface of the wafer's edge. A cleaning solution sprayingunit 400 is used to direct cleaning solution to the bottom surface ofwafer W through spraying hole 320 under a predetermined sprayingpressure. The cleaning solution contacts the bottom surface of wafer Wand is discharged to the outside of body 110 through the top surface 110c. A portion of the cleaning solution may combine with the developerliquid droplet to form a larger-sized liquid droplet P on the bottomsurface of the edge of wafer W. The liquid droplet P may drop toward theinclined portion 113 of body 110 by its own weight and may flow towardthe lower side of body 110 through inclined portion 113. The liquiddroplet P flows along inclined portion 113 and is guided into dischargehole 111 via inlet 111 a and is discharged externally through outlet 111b. Any remaining portion of liquid droplet P that did not enter inlet111 a is guided into inlet 111 a of second inclined portion 113 b and isalso discharged externally through discharge hole 111.

Liquid droplet P may also be pulled through discharge hole 111 byutilizing a vacuum suction force from vacuum suction unit 200. Inparticular, vacuum pump 220 applies a vacuum suction force to dischargehole 111 via tube 210. The vacuum suction force is applied to dischargehole 111 such that the liquid droplet P formed on the bottom surface ofthe edge of the wafer W is pulled into inlet 111 a before it dropstherein by its own weight. As a result, the liquid droplet can be forcedto flow into discharge hole 111 and can be easily discharged externallyfrom wafer W.

Alternatively, when the liquid droplet P formed on the bottom surface ofthe edge of wafer W flows or is pulled into discharge hole 111, it isguided while contacting the inclined portion of protrusion 120, wherebythe liquid droplet P is easily guided into inlet 111 a through inclinedportion 113 without splashing the top surface of inclined portion 113.

A method of cleaning the bottom surface of a wafer using thesemiconductor development apparatus in accordance with the presentinvention is described with reference to the flow chart of FIG. 5.Constituent elements for explaining the method of cleaning the bottomsurface of the wafer are the same as that referenced in theabove-described embodiments shown in FIGS. 1-4, and thus the detaileddescription thereof is omitted. Referring to FIGS. 4 and 5, chuck 190 onwhich wafer W is mounted rotates at a constant speed and is powered byan external power supply. A predetermined amount of developer issupplied to the top surface of the rotating wafer W from developersupply unit 500 at step S10. The supplied developer is uniformly spreadon the top surface of wafer W. However, the developer supplied to thetop surface of the edge of wafer W may be directed to the bottom surfaceof the wafer's edge by centrifugal force and forms a liquid droplet P. Acleaning solution is sprayed onto the bottom surface of rotating wafer Wat step S20. In particular, the cleaning solution is sprayed onto thebottom surface of the edge of the wafer W at a predetermined angle ofinclination under a predetermined spraying pressure. The cleaningsolution cleans the bottom surface of wafer W and is directed to thebottom surface of the edge of wafer W through top surface of body 110.The cleaning solution combines with liquid droplet P of the developerand forms a large-sized liquid droplet P. At step S30, any remainingdeveloper and cleaning solution on the bottom surface of the edge ofwafer W is directed down inclined portion 113 provided at the outer sidewall 110 b of knife edge ring 100 and flows into the plurality ofdischarge holes 111 provided in inclined portion 113. Liquid droplet Pmay drop onto the top surface of inclined portion 113 by its own weightand flow from the top surface of inclined portion 113 and into dischargehole 111. In this manner, liquid droplet P flows through hole 111 and isdischarged externally outside of body 110. At step S40, the droplet Pand any remaining developer and cleaning solution may be pulled intodischarge hole 111 through the use of vacuum suction supplied by suctionunit 200 and discharged externally.

FIG. 6 is a flow chart illustrating an alternative method of cleaningthe bottom surface of a wafer using the semiconductor developmentapparatus of the present invention. Referring to FIGS. 4 and 6, thedeveloper is supplied onto the top surface of the wafer W at step S100.Cleaning solution is applied to the bottom surface of wafer W and anydeveloper and/or cleaning solution remaining on the bottom surface ofthe wafer's edge flows down inclined portion 113 and into a plurality ofdischarge holes 111 provided at inclined portion 113 at step S200. Atstep S300, the developer and cleaning solution which flowed into thedischarge hole 111 is discharged externally and any remaining developerand cleaning solution is pulled to the outside using vacuum suction andsimilarly discharged.

In particular, the vacuum suction force generated from vacuum suctionunit 200 is applied to discharge hole 111. This suction force forcedlypulls liquid droplet P dropped onto the inclined portion 113 intodischarge hole 111 and discharges it externally away from body 110. Inthis manner, when the vacuum suction force is applied to discharge hole111, the suction force may be applied to the periphery of inlet 111 aprovided at the inclined portion 113 as well as to the bottom surface ofthe edge of wafer W. By utilizing vacuum suction unit 200 connected todischarge hole 111, easy cleaning of inclined portion 113 around inlet111 a and the bottom surface of the wafer's edge is achieved. Thus,liquid droplet P formed from the developer and the cleaning solutiondoes not remain on the bottom surface of the wafer's edge, therebyavoiding contamination of the top surface of wafer W by vaporization ofthe liquid droplet P deposited onto the wafer's top surface even thougha baking process is performed on wafer W.

Therefore, the liquid droplet of the developer and the liquid droplet ofthe cleaning solution formed on the bottom surface of a wafer's edgeflows into a discharge hole and is discharged externally. Alternatively,the liquid droplet is forcedly pulled away from the wafer and dischargedexternally using a suction force. In this manner a compromised circuitpattern generated during the baking process of a semiconductor wafercaused by contamination of a liquid droplet remaining on the wafer'ssurface is easily prevented. As a result, a reduction in product lossesdue to a reduction in the amount of usable wafer and a decrease inproduct deficiencies during semiconductor fabrication is achieved.

What is claimed is:
 1. A semiconductor development apparatus comprising:a chuck for supporting a semiconductor wafer; a developer supply unitfor supplying developer to a wafer, said developer supply unitpositioned a distance above said chuck; a knife edge ring disposedadjacent to a bottom surface of said wafer, said knife edge ring havinga body and a plurality of discharge holes extending through the body; acleaning solution spraying unit for spraying a cleaning solution towardsaid bottom surface of said wafer, at least a portion of said sprayingunit positioned underneath said body of said knife edge ring, whereinsaid body of said knife edge ring has an inner peripheral side facing aportion of the chuck, and an outer peripheral side, a top surface, and abottom surface, the outer peripheral side of said body of the knife edgering comprises a multi-stage inclined portion constituted by a series ofinclined outer peripheral surfaces connected to one another, each of theinclined outer peripheral surfaces subtending an obtuse angle with ahorizontal plane, the inclined outer peripheral surfaces havingdifferent inclinations from one another, and the series of connectedinclined outer peripheral surfaces only leading downwardly between thetop surface and the bottom surface of said body, and each of thedischarge holes has an inlet flush with a respective one of the outerperipheral inclined surfaces constituting said multi-stage inclinedportion such that each of the discharge holes opens to the exterior ofthe body at said one of the outer peripheral inclined surfaces, and anoutlet; and suction generating means, connected to said plurality ofdischarge holes at their outlets, for generating a vacuum in thedischarge holes that suctions developer and cleaning solution into saiddischarge holes via the respective inlets thereof.
 2. The semiconductordevelopment apparatus according to claim 1, wherein each of thedischarge holes has a cross sectional area at the inlet thereof that isgreater than a cross sectional area of said discharge hole at itsoutlet.
 3. The semiconductor development apparatus according to claim 1,wherein the inclined outer peripheral surfaces constituting saidmulti-stage inclined portion extend directly from one another betweensaid top surface and said bottom surface.
 4. The semiconductordevelopment apparatus of claim 3, wherein the inclined outer peripheralsurfaces constituting said multi-stage inclined portion comprise: afirst inclined surface descending from said top surface, and a secondinclined surface descending from said first inclined surface.
 5. Thesemiconductor development apparatus of claim 4, wherein said firstinclined surface is inclined at a greater angle relative to thehorizontal plane than said second inclined surface.
 6. The semiconductordevelopment apparatus according to claim 1, wherein said knife edge ringfurther comprises a protrusion extending from one of the inclined outerperipheral surfaces and adjacent the top surface of said body, saidprotrusion having a distal end and including an inclined surfaceextending from the distal end toward a lower portion of the outer sideof said body.
 7. The semiconductor development apparatus according toclaim 1, the cleaning solution spraying unit comprising: an inner cupsupporting said knife edge ring, the inner cup having a plurality ofspraying holes extending therein; and a cleaning solution supply unitconnected to said spraying holes to supply cleaning solution to thespraying holes.